In the prior art, there are two solutions to inject a sealing gel into a recess of a work piece known to Applicants. One of the two solutions is to inject a fluid sealing gel into the recess of the work piece with an injection mold mounted on the work piece. In this case, the fluid sealing gel is directly injected into an inner chamber of the injection mold until the fluid sealing gel fully fills the inner chamber of the injection mold. The other of the two solutions is to inject the fluid sealing gel into the recess of the work piece directly through an opening of the recess. In this case, the fluid sealing gel is injected into the recess fully.
As for the solution with the injection mold, since an injection port and a vent hole are formed in the injection mold, a residual sealing gel is generally left on the work piece at the injection port and the vent hole after finishing the injection of the fluid sealing gel. Therefore, it is necessary to remove the residual sealing gel from the work piece, taking a lot of time, and increasing the cost.
As for the solution in which the fluid sealing gel is fully injected into the recess directly through the opening of the recess, since the sealing gel can experience thermal expansion and contraction, after the fluid sealing gel is cooled and solidified, a concave surface or depression is formed at about the middle of the surface of the solidified sealing gel. This depression in the surface of the solidified sealing gel results in a surface lower than the sealing interface surface of the work piece, thereby reducing the sealing effect of the sealing gel.
FIG. 1A, FIG. 1B and FIG. 1C show the solution in which the fluid sealing gel is fully injected into the recess directly through the opening of the recess. As shown in FIG. 1A, the recess 11 is formed in the work piece 10. As shown in FIG. 1B, the fluid sealing gel 12 is fully injected directly into the recess 11. As shown in FIG. 1C, after the fluid sealing gel is cooled and solidified, because of thermal expansion and contraction, a concave surface or depression is formed at about the middle of the surface of the solidified sealing gel. This depression in the surface of the solidified sealing gel results in a surface lower than the sealing interface surface of the work piece 10, thereby reducing the sealing effect of the sealing gel.